This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The ability to target therapeutic or diagnostic proteins to the nervous system is limited by the presence of the blood-brain/nerve barriers. In this project we are testing the hypothesis that modifications of an F(ab2)2 fragment of a monoclonal antibody (IgG4.1) against fibrillar human A[unreadable]42 can be used for the molecular imaging of amyloid plaques in Alzheimer's disease (AD) using high field strength magnetic resonance microimaging (MRMI) (9.4 T). The ability of this contrast agent to image plaques in vivo in AD transgenic mice may lead to early diagnosis of AD in humans and also provide a direct measure of the efficacy of anti-amyloid therapies currently being developed.